


True to Form

by Brynncognito



Category: Good Omens (TV), Good Omens - Neil Gaiman & Terry Pratchett
Genre: Aphrodisiacs, Aziraphale Has a Penis (Good Omens), Aziraphale Has a Vulva (Good Omens), Begging, Biting, Bottom Aziraphale (Good Omens), Bottom Crowley (Good Omens), Breeding, By a VERY Loose Definition of the Term 'Female', Cloaca, Crowley Has Two Penises (Good Omens), Crowley Has a Penis (Good Omens), Crowley's Tongue (Good Omens), Crowley's True Form (Good Omens), Cunnilingus, Dirty Talk, Double Anal Penetration, Double Penetration, Double Penetration in One Hole, Double Vaginal Penetration, Female Ejaculation, Hand Jobs, M/M, Mating Plug, Other, Plot What Plot/Porn Without Plot, Rimming, Sex with Snake Form Crowley (Good Omens), Snake Crowley (Good Omens), Switching, Teasing, Top Aziraphale (Good Omens), Top Crowley (Good Omens), Vaginal Sex
Language: English
Status: Completed
Published: 2020-01-08
Updated: 2020-01-08
Packaged: 2021-02-27 16:07:55
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,320
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22169902
Author URL: https://archiveofourown.org/users/Brynncognito/pseuds/Brynncognito
Summary: Aziraphale stumbles upon herpetological interests quite by happenstance. Crowley helps him sate his curiosity.
Relationships: Aziraphale/Crowley (Good Omens)
Comments: 58
Kudos: 523
Collections: Chaotic Omens: The Fallout of a Big Bang





	True to Form

**Author's Note:**

> There's a LOT of stuff that could squick folks out. Mind the tags, more detailed warnings at the end.
> 
> Many thanks to Janthony AKA D20Owlbear for the beta~

For Aziraphale, it begins as nothing more than the kind of insatiable academic curiosity that led him to open a bookshop simply to have more of an excuse to hoard knowledge. He’d recently come across some surprisingly rare and value books on herpetology and had ended up reading about the reproduction of different types of reptiles.

He can’t help but be morbidly curious the more he reads— in particular, he’s fascinated by the reproductive anatomy of most reptiles. Aziraphale can’t get enough of it.

And eventually, as is so often the case, the mere _theoretical_ interest he has in something becomes more concrete.

“ _Angel!_ ” Crowley exclaims, sputtering, having taken a sip of the fine red wine they’d been sharing _just_ before Aziraphale asked his question. Aziraphale flatly refuses to seem apologetic, because he really _does_ want to know.

“I’m serious, Crowley. It’s _fascinating_ , and I know how shy you get about your true-form, but I just wanted to know how _true to nature_ you are when it comes to being reptilian.”

Crowley finally manages to stop coughing and wheezing from where he’s taken some of the wine down the wrong tube.

“But that’s— For Satan’s _sake_ , angel, you can’t just _ask_ someone whether they have a cloaca. And for that matter, it’s called a _vent_ , thank you very much.”

Aziraphale, oblivious to the admonishment, brightens.

“So you _do_ have one— I take it that means you have a hemipenes, as well? The theories behind how it evolved are quite fascinating, you know, although you and I _both_ know who’s actually behind all this— and it certainly isn’t Mother Nature.”

Crowley croaks a protest at that, face still visibly flushed. More embarrassingly, all this talk of reptilian traits has made his appearance slide _slightly_ toward his true-form. His fangs prick his lower lip slightly, and he can _feel_ the way his glossy black scales shimmer into appearance across his skin, small patches that quickly overshadow his freckled skin.

Aziraphale draws in his breath sharply when he realizes what’s happening, unable to resist the urge to shift in closer, holding one hand hesitantly out towards Crowley.

“Oh, my dear boy… May I?”

Crowley’s never truly been able to deny Aziraphale anything, so he nods and is rewarded with the careful way Aziraphale strokes a single finger over his scales. Everything feels _different_ when he’s in his true-form (or even partway there), and Crowley shivers as he eases up on his attempts at staying semi-human in appearance.

The rest of the change comes on as a relief, his clothing melding into the glimmering obsidian of his scales. He’s shirtless, all the better to stretch his three pairs of wings out. His face is still vaguely humanoid, but scales are visible even there. His torso is similar in that regard. 

And then, further down, the part of his anatomy that Aziraphale’s been so curious about. Embarrassingly, Crowley’s hemipenes is already protruding slightly from his vent, the spiked tips reddish pink. Aziraphale’s gaze is drawn to that hint of reptilian nature, and as Crowley flushes, his cocks stiffen further, sliding free of their home.

“Look at you,” Aziraphale murmurs, rapt, and a shiver runs down Crowley’s spine, all the way down to the very tip of his tail. “Oh, please, may I touch you?”  
  
Crowley nods, of course he does. Aziraphale runs his fingers slowly along Crowley’s length, first on one side, then the other. It feels _incredible_. All he wants is to have his thick, spiny hemipenes buried in something hot and wet. But Aziraphale has other ideas.

“This must be your ‘vent,’ then,” Aziraphale murmurs, the air quotes audible but doing nothing to detract from the eroticism of the moment. The way he probes inquisitively at the slit which houses Crowley’s reproductive anatomy feels dirty-bad-wrong but _wonderful_ at the same time. And then, Aziraphale actuallys slips a finger inside him.

Crowley hisses, writhing sinuously as Aziraphale thrusts two fingers knuckle-deep inside him, fucking his vent in a way he hadn’t even realized he’d been craving. His hemipenes bob against his stomach as he rocks against Aziraphale’s hand, coaxing him deeper and deeper. Aziraphale’s only too happy to oblige, giving him a third finger and crooking them the way he might if Crowley was sporting a cunt. Crowley shudders as Aziraphale strokes something especially pleasurable inside him, like some vestigial G-spot. 

“More,” Crowley insists, aiming for demanding and landing somewhere north of _needy_ instead. Four fingers isn’t enough, and Crowley finally yanks Aziraphale’s hand out of him, shoving Aziraphale onto his back so he can curl and wind around him. Aziraphale's trousers and pants vanish somewhere along the way, and Crowley's not sure which of them is behind the miracle. His vent’s left perfectly poised over Aziraphale’s drooling, neglected prick. He sinks down onto him with a low hiss of pleasure, and Aziraphale _groans_ so deep Crowley can nearly feel it in his bones.

It’s a tight fit, of course, made even more snug by the presence of Crowley’s hemipenes protruding from the slit, but that just makes it feel even better. Crowley undulates against Aziraphale, drawing him in deeper, and Aziraphale swears and thrusts up into Crowley’s warm, welcoming heat. He’s hotter than a true snake likely would be, but that’s likely his hellish nature asserting itself. Aziraphale, however, thinks he feels _heavenly_.

“Do you _like_ how that _feelssss_ , angel? Have I _sssatisssfied_ your _curiosssity_ yet?” Crowley coos, low and sibilant, though his attempts at sounding seductive are somewhat hindered by the strained quality to it, the pleasure too much to be denied.

“You feel— Oh, Crowley,” Aziraphale breathes, seemingly beyond words. And it isn’t just being inside Crowley that has him overcome. His hands never stay still for more than a second or two at a time, too busy memorizing the precise pattern of Crowley’s scales. Crowley’s tail winds itself more firmly about Aziraphale’s waist, and he gives a squeeze of his inner muscles that makes Aziraphale gasp, his hips giving a little twitch that rubs up against Crowley’s insides in a particularly enjoyable way.

“Oh— That’s so good, Crowley, I— Please, can I…?” As if Aziraphale _really_ needs to ask permission to touch Crowley, when he’s already balls-deep inside him. But Crowley simply smirks in response, squirming up against Aziraphale in a way that makes his hemipenes rut wetly against Aziraphale’s soft stomach. 

“Go ahead,” Crowley purrs, and Aziraphale reaches for him with both hands, hedonistic thing that he is. Each hand wraps into a tight fist around one part of Crowley, giving his hemipenes a few long, slow strokes that would make Crowley’s eyelids flutter if they hadn’t vanished with his transformation. Instead, he hisses in appreciation, a slow stream of slippery, viscous precome oozing from the tips. 

“I can only imagine how these must feel inside someone,” Aziraphale muses, and Crowley bites down on a groan, because he is _not_ going to last long if he thinks about burying his hemipenes inside Aziraphale. _Fuck_ , he could fuck him with both of them in one hole, or possibly Aziraphale would be willing to try on a cunt for _experimental_ reasons.

“Would you like to _feel_ , angel?” Crowley murmurs, his tongue flickering out against Aziraphale’s earlobe, tasting the scent of his arousal thick in the air. 

Oh, goodness, I—” Aziraphale seems almost flustered by the idea, and Crowley gives a low, suitably demonic chuckle as he _constricts_ around him.

“ _Firsssst_ I think you should give me your _sssseed_ ,” Crowley hisses, and Aziraphale’s mouth falls open as he gives another helpless thrust into Crowley’s vent. His fingers flutter uncertainly where they’re wrapped around Crowley’s hemipenes, and he eventually settles for releasing one of them (with obvious reluctance) so he can grip Crowley’s sharp hipbone with the other.

“Crowley, I—” Aziraphale groans and lets his head fall forward, brushing open-mouthed kisses against Crowley’s throat as he thrusts into Crowley’s vent over and over again. Crowley moves in time with him, serpentine, rhythmically clenching around him in a way that soon tips him over the edge. The sensation doesn’t quite make Crowley come, but it’s a near thing. He tucks the memory away immediately for later perusal, sure he’ll enjoy getting off to it for _centuries_ to come.

“Oh, God,” Aziraphale finally manages, half-collapsed underneath Crowley, his come visibly oozing out around his prick where it remains buried in Crowley’s slit. 

“I don’t think _Ss_ _ _s_ he hasssss _ anything to do with _thisss_ ,” Crowley retorts with another low chuckle when Aziraphale’s body gives a bit of a spasm, aftershocks clearly still rolling through him.

Finally, Crowley is the one to pull up and off Aziraphale, though he immediately shoves three fingers into himself, enjoying the slippery, sticky mess Aziraphale’s made of his opening. Aziraphale can’t help but watch, mouth open and eyes half-glazed with lust, as Crowley fucks himself for a few idle moments, finally slipping his fingers free only to pop them into his mouth. His agile tongue easily coaxes every drop of Aziraphale’s seed from his digits, though he doesn’t enjoy the taste _nearly_ as much as Aziraphale’s expression as he does so.

“My turn,” Crowley finally croons, when he’s finished putting on a show. His hemipenes are flushed a darker shade now with his arousal, oozing precome steadily. They’re fat and spiney, at least as thick _each_ around as Aziraphale’s prick. But Aziraphale seems conflicted again, and Crowley pauses.

“ _Unlesss_ you’d prefer not to?” Crowley adds, uncertainly, and Aziaphale quickly moves to reassure him.

“No! I mean, yes! I’d love to. I just…” He bites down on his lower lip. “I don’t know whether I’d like to take you in my arse or my cunt. Or both.”

Crowley _growls_ in approval, a low, predatory thing that’s more infernal than reptilian.

“ _Ssssuch_ a difficult _choice_ . _Perhapsss_ I should _sssstart_ with your cunt.” Aziraphale visibly swallows, then nods, and Crowley’s almost sorry to see his lovely cock vanish. But the cunt which replaces it is equally tasty, already slick and pink and swollen. Crowley immediately surges forward, and Aziraphale gives a startled squeak when Crowley’s arms hook under his thighs and he dives down between them to taste it properly. His forked tongue flickers over Aziraphale’s clit at first, caressing it and stroking it in a way that makes Aziraphale’s thighs shake. But a second later, he’s exploring the slippery folds down below, making Aziraphale moan breathlessly. And then, there’s the slick, _wet_ opening itself, which Crowley eagerly plunders with his sinuous tongue, claiming his hot nectar. Aziraphale gasps and bucks his hips, clear encouragement to continue. 

Crowley’s tongue thrusts deeper, caressing Aziraphale’s insides and seeking out that soft, spongy bit that he knows feels better than anything else. He finally strokes his tongue over it directly, pressing up against it with surprising strength for such a slender appendage. Aziraphale gives a choked cry, tangles his fingers in Crowley’s hair, and rocks against him more urgently. Crowley doesn’t ease up, however, until Aziraphale’s coming with a _shout_ , a gush of sweet juices coating Crowley’s tongue and chin as he ejaculates. Crowley hums in satisfaction as he takes his time savoring it, until Aziraphale’s whining and squirming beneath him. Only then does he pull back, slithering up Aziraphale’s body so he can share Aziraphale’s sweet, sweet taste with him.

Aziraphale’s legs wrap around Crowley immediately, his hemipenes rubbing up against Aziraphale’s dripping wet cunt while they kiss, and Aziraphale’s almost ravenous in the way he claims his own juices from Crowley’s tongue, even lapping it from his chin while Crowley hisses in approval and ruts against him.

“Please,” Aziraphale begs, breathless and needy in a way that Crowley simply can’t resist. He’s so slick and open that it’s almost too easily for both Crowley’s fat appendages to slide inside, despite the way it stretches him open almost obscenely. Aziraphale’s breath catches in his throat for a moment before he lets out a _desperate_ groan, and Crowley swears as he writhes against Aziraphale, burying his thick, spined hemipenes even further inside him.

“Oh, _Crowley_ ,” Aziraphale manages to get out, as Crowley coils himself around Aziraphale’s well-padded midsection, glossy red-and-black scales sliding against him as Crowley’s lower body undulates, thrusting his reptilian cocks into Aziraphale. He doesn’t properly _thrust_ so much as he does _squirm_ , little movements of his body making his hemipenes rock inside Aziraphale. The angel can’t seem to get enough, either, making up for Crowley’s lack of proper hips with the movement of his own, fucking himself wantonly on Crowley’s fat pricks.

“You want me to _breed_ you, angel?” Crowley hisses, as the pleasure begins to coil low in his belly, warning him of his impending climax. Aziraphale can only nod helplessly, gasping out another desperate plea. Crowley’s coils wind themselves even tighter around him as his hemipenes rock in and out of Aziraphale, the spines not _sharp_ so much as torturously pleasurable. When he finally throbs inside Aziraphale and shoots his seed inside him, Aziraphale can’t help but come again, his hot cunt rippling around Crowley’s hemipenes in an attempt to milk him absolutely dry. Crowley’s only too happy to oblige, spilling _years_ of pent-up demonic essence inside him, until Aziraphale’s stomach begins to visibly swell.  
  
When he’s finally finished, his cocks giving another few twitches, Aziraphale protests as he starts to withdraw. He clenches down around Crowley, trying to keep him in place— but finds he has something entirely different filling him, keeping him plugged up.

“Crowley? Is… that?”

“Mmmm. I believe you would call it a _mating plug_ ,” Crowley purrs, nuzzling into Aziraphale’s neck and nipping at it lightly with his fangs. He contemplates injecting him with his potent, aphrodisiac venom but decides against it for now. There’s always next time. (At least, he desperately hopes so.)

Aziraphale shivers, finding the thought of being _plugged_ more arousing than Crowley’d expected. He smirks, his forked tongue scenting the still-heavier scent of commingled arousal in the air. The room smells like lust and sex and sweat, and it’s absolutely intoxicating. Crowley’s hemipenes haven’t fully softened just yet, and given he is a _demon_ , he sternly instructs them to perk up a bit. After all, he _has_ promised to fuck both of Aziraphale’s holes.

“Tell me, angel, have you ever been fucked in the _arssssse_ before?” Crowley murmurs, making Aziraphale swallow convulsively. His gaze flickers toward Crowley with a hint of genuine alarm, as if he’s not sure what the right answer here is. Crowley’s expressions softens minutely, reptilian as it is at the moment, and he brushes a soft, genuine kiss against the corner of Aziraphale’s mouth in reassurance. “Irrelevant,” he purrs, letting his fangs scrape lightly against Aziraphale’s jawline, not quite breaking the skin. “ _It’ssss_ **mine** , now, _regardlessss_.” 

Crowley considers summoning a bottle of lube but decides otherwise at the last minute. He has a much better idea. Manhandling Aziraphale in his true-form is easy enough, and Aziraphale simply squawks once in surprise as he’s toppled backward, Crowley flipping him onto his stomach and coaxing him up onto all fours (or at least nudging him up onto his knees).

“Mmmm, I could eat you _up_ , angel,” Crowley purrs, spreading that deliciously plump arse wide open so he can get a glimpse of the tight, pink pucker he’s soon to violate. He wastes little time in moving in to claim it, forked tongue caressing it at first as he breathes in Aziraphale’s unique, slightly musky aroma from so very close to the source. Aziraphale whimpers at that, legs spreading wider in encouragement, and Crowley responds accordingly. It’s almost _too_ easy to thrust his slender tongue inside Aziraphale, winding almost impossibly deep inside him and exploring his every crevice.

“ _Crowley_ , oh, _God_ ,” Aziraphale gasps out, face mashed against the floor beneath him as he rocks back against Crowley’s face. Deadly-sharp talons dig into the soft flesh of Aziraphale’s rump as Crowley spreads him open, drawing tiny pinpricks of blood. Aziraphale doesn’t seem to mind, hardly even seems to notice (or perhaps, draws even greater pleasure from it) as Crowley leisurely tongue-fucks him open. Crowley doesn’t stop, either, until Aziraphale’s nearly babbling in Enochian, begging Crowley to fuck him, and dripping wet with saliva.

Crowley withdraws with only a hint of reluctance, enjoying the way Aziraphale’s hole slips closed around the very tip of his tongue on its way out, like he’s desperate to stay filled even by that slender appendage. But Crowley has something much better to fill Aziraphale with. He raises himself up a bit higher on his glossy black-and-red coils, rubbing his reddish pink hemipenes against the cleft of Aziraphale’s arse just to draw another desperate whimper from him. Then, and only then, does he grip them tightly in one clawed hand to force them inside Aziraphale’s tight arse.

It’s questionable which of them groans more loudly as Crowley’s spiny members push their way inside Aziraphale, and Crowley grips Aziraphale’s hip tightly in one hand as he sinks inside him painstakingly slowly. Snakes aren’t particularly prone to perspiration, but that doesn’t stop the sweat from pricking Crowley’s brow by the time he’s finally buried in Aziraphale to the hilt, filling him up with both of his fat reptilian dicks. Crowley stills for a moment then, breathing heavily, both of them too overwhelmed by the sensation to do much more than _breathe_ and give their bodies time to adjust, lest the slightest movement tip them over the edge already.

After a time, Aziraphale shifts a little, presses back against Crowley in a way that clearly indicates he’s ready for more. Only then does Crowley _move_ . In this form, he’s not truly able to _thrust_ as such, but his reptilian form undulates in a way that rock his thick hemipenes back and forth inside Aziraphale, the spines just this side of _too much_ in the way they rub and scrape up against his insides. Aziraphale doesn’t have a prostate at the moment, but being fucked like this is no less pleasurable for it, and he gives small sounds of approval every time Crowley’s cocks shift inside him again— moans and gasps and whimpers that are absolute music to Crowley’s ears.

“Do you _like_ being filled up like _thisss_ , angel?” Crowley coos, winding his powerful coils more tightly around Aziraphale as he fills him up. “Want me to fill you up even more with my _sssseed_?” Aziraphale nearly sobs at that, nods his head desperately and rocks his hips back against Crowley, clenching around him as if that wasn’t answer enough. “ _Good_ ,” Crowley hisses, and he finally, finally gives into temptation and sinks his fangs deep into Aziraphale’s throat. The pain and the sensation of being pumped full of aphrodisiac combined tip Aziraphale over the edge, and he _screams_ as he clenches down Crowley again and comes untouched. The spasmodic ripples of Aziraphale’s inner muscles do their job quite effectively, too, tipping Crowley over the edge as well. He shivers as his cocks throb inside Aziraphale, and he spills his load deep inside him, filling him up quite impressively considering it’s his second time in less than 30 minutes. 

When Crowley withdraws this time, he leaves behind the exact same sort of plug, thick and waxy and well-suited to the task of keeping Aziraphale filled up with his seed for as long as he likes. Aziraphale gives a tiny whimper before finally collapsing, breathing heavily. Crowley wraps his coils around him in a gentle embrace, his arms pulling Aziraphale in close as he flicks his tongue out against Aziraphale’s neck, breathing deeply of the heavy scent of his arousal, still unmistakable despite how many times he’s come now. 

Crowley chuckles as he presses his lips to Aziraphale’s throat where he can feel his pulse racing and slides a clawed hand down between Aziraphale’s thighs once more. With Crowley’s venom running through his veins, he’ll surely have five or six more orgasms in him yet.

**Author's Note:**

> They don't plan things out terribly well, so that could be consensually iffy. Also Crowley injects Aziraphale with his venom at one point, which serves as an aphrodisiac. And he plugs Aziraphale up with his seed after he comes in him, without asking. Also, lots of monsterfuckery here. Crowley has a hemipenes and cloaca. Filthiness happen with both.
> 
> Your comments sustain me. Also, if you like this enough, there may be sequel(s) in the future.


End file.
